Sun Valley Mercedes Transmissions

 Remanufactured Mercedes Benz automatic transmissions

11239 iLex Ave.  Unit B
Pacoima, Ca. 91331
 818 7822300

 Phone: 818 782 2300      E Mail:



Apply a small amount of light grease to the snout of the fluid coupler. This will prevent scouring of the front pump bushing. Pour one quart of ATF into the fluid coupler before installation into the transmission. This will prevent an air lockout of the ATF. Flush out and blow out the transmission oil cooler lines. Continue until all of the debris is removed from the lines and oil cooler.

 The first set of  these instructions will pertain to the double acting solenoid that is located on the top of the transmission just behind the bell housing. This solenoid controls normal driving modulator pressure, kick down modulator pressure and deceleration modulator pressure. The wires to this solenoid must be installed properly. The control switches to this solenoid must be in good working order. The idle and deceleration switch is located on the front carburetor or on the throttle valve of a fuel injected engine. Operational problems arising from this solenoid are as follows: No kick down, early shift, early slip shift, slipping in all gears, late shift, clunking during deceleration downshift when the car is slowing to a stop. Any or all of these problems could also be intermittent.

1) Move the solenoid's rod up and down manually to assure free movement. There should be more spring tension pushing the rod down than lifting it up. If it is binding, there may have been some damage caused during shipment or installation. If this has happened, call us.

2) Look at the wires that are connected to the terminal block on the left side of the bell housing. The size of the eyelet on the different colored wires will dictate which wires should be connected to each other. Large hole with large hole, etc. It is easy to mix up the Green/Red wires. The Green/Red wires attach to the servo pressure switch located on the side of the transmission. One wire will connect to the left pressure switch and go up and over the top of the transmission to the other pressure switch (if your trans has that switch). These switches cause the fast idle solenoid to activate when the car is put into D or R. if the configuration is correct, you should have 6 wires connected to the terminal block, 3 wires connected to the left pressure switch and one wire connected to the right pressure switch.

3) Have someone sit in the car with the key on, but the engine off. The fuel pump should be running. Make sure the emergency brake is set. With the throttle in idle position, the double acting solenoid should be in the down position. Touching the throttle lightly moving the throttle into off idle position up to approximately 3/4 throttle, the solenoid should be in the center position. If this action does not occur, check the fuses in the fuse box. If they are OK, check the switch located on the front carburetor of the fuel injection throttle body. If the switch is bad, replace it.

4) Push the throttle to the floor, depressing the kick down switch below the foot petal. The double action solenoid should lift. If this does not occur, bypass the kick down switch to see if it is working properly. If not, replace the kick down switch.

5) Some early cars have the throttle switch and kick down switch built into the gas petal. Same procedures (listed above) apply.

This section pertains to the vacuum modulator

Adjust the modulator only after you have verified the proper function of the double acting solenoid. The modulator tells the transmission when to shift and it determines the quality of shift. The modulator pressure should be set at around 4 Bar at idle with no vacuum line attached. This setting will give you a place to start, however, the modulator pressure should be set according to the operation of the car. Remember: Early and/or slip shift is low modulator pressure. Late and/or hard shift is high modulator pressure. These transmissions start in 2nd gear unless it starts off at full throttle, or the gear selector is in low. The fluid coupler (torque converter) makes the transmission feel like it is slightly slipping (750 RPM) until it quickly hooks up.

1) Remove the vacuum line from the modulator assembly on the transmission with the engine running. There should be at least 15 inches of vacuum at the line.

2) Check the modulator pressure at the test port to make sure you have around 4 bar at idle with no vacuum.

3) Install the vacuum line and drive the car. If it shifts too early, you need to raise the modulator pressure. You do this by loosening the lock nut on the small shaft in the center of the vacuum modulator. Turn this small shaft in (clockwise) 1/2 turn. Tighten the lock nut while holding the adjuster shaft in place. Repeat until the shift is correct. If the complaint is late or hard shift, follow the same procedure except turn the adjustment shaft out (counter clockwise) to lower the modulator pressure.

Some operational problems may be caused by valves in the valve body reacting slowly due to the bores being freshly honed. These symptoms will go away after a few days of driving.

If you have any questions, please call or E mail us!

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                                                       SUN VALLEY MERCEDES TRANSMISSIONS                                                 

11239 iLex Ave.  Unit B
Pacoima, Ca. 91331
 818 7822300


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